Conventionally, there have been disclosed technologies for detecting a face region including a face of a person from an image taken with the person as a subject, and correcting the image based on a feature amount of the face region. For example, Patent Document 1 describes a technology in which a face region is first detected, the race, the age, the gender, etc, of a subject are then estimated using the characteristic amounts of the detected face region, and correction parameters matching the estimated results are set to adjust the skin color of the face region and correct brightness against backlight.
In this case, the technology of Patent Document 1 divides races and ages into categories, sets a correction item for each combination of the categories, genders, and the presence or absence of backlight, generates a setting table, in which an increase-decrease amount or an increase-decrease rate of each gradation is set, as a correction parameter for each item, and stores the generated tables in a memory. Then, the estimated results of the races, the ages, the genders, etc, of subjects are matched with the setting tables to read the correction parameters corresponding to the estimated results.
However, the technology of Patent Document 1 does not specifically describe how to set an increase-decrease amount or an increase-decrease rate of each gradation. In addition, the adjustment of skin colors, the correction of brightness against backlight, blemish removal processing, and the smoothing correction of skins are only illustrated as correction contents.
Therefore, the technology of Patent Document 1 seems to be useful for a case in which the brightness of an entire face region is uniformly corrected as in brightness correction against backlight. However, the technology of Patent Document 1 does not specifically describe a method of setting an increase-decrease amount or an increase-decrease rate of each gradation. Therefore, it is difficult to obtain the effect of illuminating a shaded area according to the surface of the face of a person and the direction of a light source as in, for example, a case in which a shaded area of a face is illuminated using a reflection plate often used to actually take an image of a person.